broke lockback

[little d.]

i was at trade day yesterday and the guy selling next to me had a puma lock blade that for some reason the lock pin fell out while someone was looking at it. later on i was looking at it trying to see what had happened to it, the back spring that had fell out didn't look broke it just looked as it had fell out of place. the knife was a older model that had some nice stag handles. i was hoping that someone could tell me about this kind of problem and if it could be a easy fix, i can get it cheap taking it in on a trade. i didn't get the model number but it is about 4 inches closed and looks sorty like a lb5 schrade. thanks for any help.

[Elvis]

If all the visible parts appear intact, it may be a lockback with the construction method that requires a small hard metal rod inside. It's what provided the spring action as you apply pressure to release the blade from the open position. If it's gone I can see where there wouldn't be enough pressure to hold the works together. Once you find the right diameter steel rod, the hard part is figuring out the correct length for your knife. Too long and it opens too hard, and too short and it will be too soft to press. Maybe just buy enough for more than one try. Oh yeah, you can do all of this without taking the knife apart too. Good luck!

[just bob]

Maybe someone will post a tutorial on the repair of a lockback. I have never had one apart and really don't know how they work. It would be interesting.

[Elvis]

A couple of good pictures of one already apart along with a brief explaination of the works should help. I'll take care of the pics today and post them this evening.

[jerryd6818]

Bob - Dale explained those lock mechanisms in a recent thread, with pictures.
http://www.allaboutpocketknives.com/kni ... 49#p267249

[just bob]

Thank you for posting that link. I wish I had seen that before. There is so much info on here. It is hard to keep straight which forum you saw something in.

[Elvis]

Thanks Jerry (and Dale). The steel rod (spring) is clearly shown there and the design kind of explains itself.

[just bob]

Here is the locking assembly on a Case P1051½ SSP. This is a cheap knife and if you compare it to Dale's pics it has a different mechanism for operation. The tail pc on this is either plastic or fiber. I had never had one of these apart and bought this in a junk box with broken handles on it.I thought this was a cheap opportunity to experiment on. It will have fiber handles when it's done.

[orvet]

There are several variations of the same principal.
Here is a Kershaw Wiley that is partially apart for new handles.
It uses the two flat springs like Schrade used in later years.

At least some of the Kershaw Wild Turkeys used the spacer and bar like the earlier Schrades.

The principal is the same in all these locks though the parts & shape varies.
A piece of spring steel (held in place by a spacer or 2 flat pieces) pushes up on the lock bar to engage the locking lug into the lock notch in the round end of the tang.


It might be interesting to see other variations of this principal if anyone has pics or if they discover any new ones in knives they are working on.